International audience ; A preliminary reflection to the definition of a PhD research problem on the concepts of participation, landscape and project, led the student to be interested in the participatory processes of landscape management projects design, and in the inhabitants landscapes representations. The method includes the comparative analysis of local processes of projects design, and the direct observation of two Walloon landscape management projects design (investigation conducted with stakeholders implied in the project design and among inhabitants, direct observation, organisation of participative meeting-debates. Fitting her research approach within the field of the territorial participative research-action, the PhD student assumes that the participation of the territorial actors and the population can "feed" the scientific research as well as territorial action. She reconsiders moreover some difficulties encountered in her research.